To all who could sanely judge, it had become clear that the crusades were at once a vast drain on the blood and treasure of Europe and a vast force of demoralization. In the course of the fifth, the government of Venice succeeded in using the crusaders, in despite of the protests of Innocent III, to wrest the city of Zara from the king of Hungary, himself a zealous crusader. Then the expedition, with the pope's approval, proceeded to interfere in Byzantine strifes, making and unmaking emperors, until they had created chaos, whereupon they sacked Constantinople (1204) with every circumstance of vileness and violence. The pope, who had hoped to reconcile the Byzantines to papal rule, burst out in bitter indignation at the deeds of the men to whom he had given his indulgences; but morality was at an end all round, as might have been foretold; and the pope accepted the conquest for what it was to bring him in new power. Christendom thenceforth crusaded with its tongue in its cheek. From the first the papacy had taught that no faith need be kept with unbelievers; and so was given a very superfluous apprenticeship to bad faith between Christians. When in 1212 there broke out the hapless Children's Crusades, out of the 30,000 who followed the boy Stephen some way through France, 5,000 were shipped at Marseilles by merchants who, professing to carry them "for the cause of God, and without charge," sold them as slaves at Algiers and Alexandria. The last recruits furnished by pope Nicholas IV to the Grand Master of the Templars were drawn from the jails of Italy: the papacy itself had ceased to put any heart in the struggle. It is a reasonable calculation that in the two centuries from the first crusade to the fall of Acre (1291) there had perished, in the attempts to recover and hold the Holy Land, nine millions of human beings, at least half of them Christians. Misery and chronic pestilence had slain most; but the mere carnage had been stupendous.